tools: add disassembler helper for files .inc

We are moving the binary helpers in files .inc in contrib/loaders/
but we have no support to disassemble them for checking their
content, nor documentation to give any hint.

Add a simple script that uses objdump to directly disassemble a
file .inc
Use Cortex-M settings as default, but provide the flexibility to
reuse the script for any other target CPU.

Change-Id: I12e79580f2936b1622fb7231d9a2484a763ba72a
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7347
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

tools/disassemble_inc.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# Simple script to disassemble a file .inc generated by
+# src/helper/bin2char.sh
+# Can be useful to check the correctness of the file .inc
+#
+# By default it decodes ARM thumb little-endian, e.g. cortex-m.
+# Set CROSS_COMPILE for other toolchains.
+# Set OBJDUMP_FLAGS for different objdump flags.
+#
+# Usage:
+#   contrib/loaders/disassemble_inc.sh file.inc
+
+default_CROSS_COMPILE="arm-none-eabi-"
+default_OBJDUMP_FLAGS="-m arm -EL -M force-thumb"
+
+if [ $# != 1 -o ! -f "$1" ]; then
+	echo "Usage:"
+	echo "    $0 path/to/file.inc"
+	echo ""
+	echo "Set CROSS_COMPILE and/or OBJDUMP_FLAGS to override current default:"
+	echo "    export CROSS_COMPILE=\"${default_CROSS_COMPILE}\""
+	echo "    export OBJDUMP_FLAGS=\"${default_OBJDUMP_FLAGS}\""
+	exit 1
+fi
+
+if [ -z "${CROSS_COMPILE}" ]; then
+	CROSS_COMPILE="${default_CROSS_COMPILE}"
+fi
+
+if [ -z "${OBJDUMP_FLAGS}" ]; then
+	OBJDUMP_FLAGS="${default_OBJDUMP_FLAGS}"
+fi
+
+perl -v > /dev/null 2>&1
+if [ $? != 0 ]; then
+	echo "Error: 'perl' interpreter not available."
+	exit 1
+fi
+
+tmpfile=$(mktemp --suffix=.bin)
+
+echo "Disassemble $1:"
+echo "${CROSS_COMPILE}objdump ${OBJDUMP_FLAGS} -b binary -D ${tmpfile}"
+
+perl -e 'while (<>){while ($_=~/(0x..)/g){print chr(hex($1));}}' $1 > ${tmpfile}
+${CROSS_COMPILE}objdump ${OBJDUMP_FLAGS} -b binary -D ${tmpfile}
+
+rm ${tmpfile}